(1) Field of the Invention
The present invention relates to vehicular control apparatus and method for a shift-by-wire device.
(2) Description of Related Art
Some types of vehicles have shift position sensors for detecting shift positions (selection ranges) selected by operations of vehicle operators (vehicle drivers) and have driven actuators based on the detected selection ranges to operate manual valves and parking mechanisms of automatic transmissions. In such vehicles as described above, there are mechanical devices (links) used for interlocking operations of manual valves of the automatic transmissions and the parking mechanisms with shift lever operations. These mechanical devices are replaced with electrical mechanisms and have referred to as, so-called, shift-by-wire vehicles.
Some shift-by-wire vehicles have functions to automatically change the shift position s of the automatic transmissions to vehicular parking ranges (so-called, P ranges) (auto-parking functions) when ignition switches or power switches are switched to OFF positions.
In addition, some other types of the shift-by-wire vehicles have functions (auto-parking functions) to be switched automatically to P ranges with the ignition switches or the power switches in the OFF positions and with no selections of the P ranges from among the shift-by-wire vehicles in which switches additionally attached separately from the shift levers (Parking switches) are used to switch the selection or non-selection of P ranges.
In the shift-by-wire vehicles having the auto-parking functions, when the ranges are switched into P ranges, revolutions of output shafts of the automatic transmissions are blocked through the parking mechanisms and the automatic transmissions are in the parking states by which vehicle road wheels are not revolved so that the vehicles are not moved.
In an assembly line of the vehicles, such a line that only one side road wheels from among left and right road wheels are mounted on a belt conveyer and the other side road wheels run spontaneously is widely known (a line in which a single sliding conveyer has been adopted). In the assembly line in which the single sliding conveyer has been adopted, in a case where the shift-by-wire vehicles in which the auto-parking function is provided are conveyed, the revolutions of the road wheels are blocked due to the operations of the parking mechanisms so that the road wheels not mounted on the belt conveyer are drag out.
Therefore, while the assembly line conveys the shift-by-wire vehicles, the ignition switches or the power switches cannot be switched to the OFF positions so that electric power consumptions are carried out for the vehicle batteries. In addition, it is necessary to switch the ignition switches or the power switches in the ON position or the OFF position for all of the vehicles so that a total operation cost to assembly the vehicles is increased.
Two Japanese Patent Application Publications of JP2003-080967 published on Mar. 19, 2003 and JP2007-170546 published on Jul. 5, 2007 exemplify the shift-by-wire vehicles in which the auto-parking functions are provided and P ranges (operations of the parking mechanisms) can be released under constant conditions.
The former Japanese Patent Application Publication No. JP2003-080967 published on Mar. 19, 2003 discloses a vehicular control apparatus in which a changeover switch to release P range is provided. In this apparatus, the switch is operated with no insertion of an ignition key into a key cylinder so that the shift range can be changed from P range to the neutral range (“N”) range.
The latter Japanese Patent Application Publication No. JP2007-170546 published on Jul. 5, 2007 discloses the shift-by-wire vehicle in which the change of the shift range is carried out according to the operations of changeover switches. In this vehicle, when the ignition switch is switched to the OFF position after the input of the N range switch, the shift ranges of the automatic transmission are set to N (neutral) range not to P range.